Tar sands are a very significant source of carbonaceous material. It is known in the art that carbonaceous materials can be recovered from tar sands in various ways. One process that has been described and is commercially used is a hot water extraction of tar sands. In this process, sodium carbonate and hot water is used for frothing the bitumen. This process involves the use of water and is therefore associated with various problems reaching from the phase separation to environmental concerns.
It also has been proposed to use supercritical extraction of tar sands (see for instance British Pat. No. 1,495,722). A remaining goal in the industry is to provide integrated processes that are energy efficient and yet relatively simple. An additional particular problem encountered in the recovery of carbonaceous materials from tar sands resides in the fact that very fine sand particles are associated with the material and these are normally entrained in the product recovered and have to be removed. This step is both technically difficult and economically demanding.